Merge branch 'dd/send-email-config'
[git] / refs.c
1 /*
2  * The backend-independent part of the reference module.
3  */
4
5 #include "cache.h"
6 #include "config.h"
7 #include "hashmap.h"
8 #include "lockfile.h"
9 #include "iterator.h"
10 #include "refs.h"
11 #include "refs/refs-internal.h"
12 #include "run-command.h"
13 #include "object-store.h"
14 #include "object.h"
15 #include "tag.h"
16 #include "submodule.h"
17 #include "worktree.h"
18 #include "strvec.h"
19 #include "repository.h"
20 #include "sigchain.h"
21
22 /*
23  * List of all available backends
24  */
25 static struct ref_storage_be *refs_backends = &refs_be_files;
26
27 static struct ref_storage_be *find_ref_storage_backend(const char *name)
28 {
29         struct ref_storage_be *be;
30         for (be = refs_backends; be; be = be->next)
31                 if (!strcmp(be->name, name))
32                         return be;
33         return NULL;
34 }
35
36 int ref_storage_backend_exists(const char *name)
37 {
38         return find_ref_storage_backend(name) != NULL;
39 }
40
41 /*
42  * How to handle various characters in refnames:
43  * 0: An acceptable character for refs
44  * 1: End-of-component
45  * 2: ., look for a preceding . to reject .. in refs
46  * 3: {, look for a preceding @ to reject @{ in refs
47  * 4: A bad character: ASCII control characters, and
48  *    ":", "?", "[", "\", "^", "~", SP, or TAB
49  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
50  */
51 static unsigned char refname_disposition[256] = {
52         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
53         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
54         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
55         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
56         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
57         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
58         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
59         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
60 };
61
62 /*
63  * Try to read one refname component from the front of refname.
64  * Return the length of the component found, or -1 if the component is
65  * not legal.  It is legal if it is something reasonable to have under
66  * ".git/refs/"; We do not like it if:
67  *
68  * - it begins with ".", or
69  * - it has double dots "..", or
70  * - it has ASCII control characters, or
71  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
72  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
73  * - it ends with a "/", or
74  * - it ends with ".lock", or
75  * - it contains a "@{" portion
76  *
77  * When sanitized is not NULL, instead of rejecting the input refname
78  * as an error, try to come up with a usable replacement for the input
79  * refname in it.
80  */
81 static int check_refname_component(const char *refname, int *flags,
82                                    struct strbuf *sanitized)
83 {
84         const char *cp;
85         char last = '\0';
86         size_t component_start = 0; /* garbage - not a reasonable initial value */
87
88         if (sanitized)
89                 component_start = sanitized->len;
90
91         for (cp = refname; ; cp++) {
92                 int ch = *cp & 255;
93                 unsigned char disp = refname_disposition[ch];
94
95                 if (sanitized && disp != 1)
96                         strbuf_addch(sanitized, ch);
97
98                 switch (disp) {
99                 case 1:
100                         goto out;
101                 case 2:
102                         if (last == '.') { /* Refname contains "..". */
103                                 if (sanitized)
104                                         /* collapse ".." to single "." */
105                                         strbuf_setlen(sanitized, sanitized->len - 1);
106                                 else
107                                         return -1;
108                         }
109                         break;
110                 case 3:
111                         if (last == '@') { /* Refname contains "@{". */
112                                 if (sanitized)
113                                         sanitized->buf[sanitized->len-1] = '-';
114                                 else
115                                         return -1;
116                         }
117                         break;
118                 case 4:
119                         /* forbidden char */
120                         if (sanitized)
121                                 sanitized->buf[sanitized->len-1] = '-';
122                         else
123                                 return -1;
124                         break;
125                 case 5:
126                         if (!(*flags & REFNAME_REFSPEC_PATTERN)) {
127                                 /* refspec can't be a pattern */
128                                 if (sanitized)
129                                         sanitized->buf[sanitized->len-1] = '-';
130                                 else
131                                         return -1;
132                         }
133
134                         /*
135                          * Unset the pattern flag so that we only accept
136                          * a single asterisk for one side of refspec.
137                          */
138                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
139                         break;
140                 }
141                 last = ch;
142         }
143 out:
144         if (cp == refname)
145                 return 0; /* Component has zero length. */
146
147         if (refname[0] == '.') { /* Component starts with '.'. */
148                 if (sanitized)
149                         sanitized->buf[component_start] = '-';
150                 else
151                         return -1;
152         }
153         if (cp - refname >= LOCK_SUFFIX_LEN &&
154             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN)) {
155                 if (!sanitized)
156                         return -1;
157                 /* Refname ends with ".lock". */
158                 while (strbuf_strip_suffix(sanitized, LOCK_SUFFIX)) {
159                         /* try again in case we have .lock.lock */
160                 }
161         }
162         return cp - refname;
163 }
164
165 static int check_or_sanitize_refname(const char *refname, int flags,
166                                      struct strbuf *sanitized)
167 {
168         int component_len, component_count = 0;
169
170         if (!strcmp(refname, "@")) {
171                 /* Refname is a single character '@'. */
172                 if (sanitized)
173                         strbuf_addch(sanitized, '-');
174                 else
175                         return -1;
176         }
177
178         while (1) {
179                 if (sanitized && sanitized->len)
180                         strbuf_complete(sanitized, '/');
181
182                 /* We are at the start of a path component. */
183                 component_len = check_refname_component(refname, &flags,
184                                                         sanitized);
185                 if (sanitized && component_len == 0)
186                         ; /* OK, omit empty component */
187                 else if (component_len <= 0)
188                         return -1;
189
190                 component_count++;
191                 if (refname[component_len] == '\0')
192                         break;
193                 /* Skip to next component. */
194                 refname += component_len + 1;
195         }
196
197         if (refname[component_len - 1] == '.') {
198                 /* Refname ends with '.'. */
199                 if (sanitized)
200                         ; /* omit ending dot */
201                 else
202                         return -1;
203         }
204         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
205                 return -1; /* Refname has only one component. */
206         return 0;
207 }
208
209 int check_refname_format(const char *refname, int flags)
210 {
211         return check_or_sanitize_refname(refname, flags, NULL);
212 }
213
214 void sanitize_refname_component(const char *refname, struct strbuf *out)
215 {
216         if (check_or_sanitize_refname(refname, REFNAME_ALLOW_ONELEVEL, out))
217                 BUG("sanitizing refname '%s' check returned error", refname);
218 }
219
220 int refname_is_safe(const char *refname)
221 {
222         const char *rest;
223
224         if (skip_prefix(refname, "refs/", &rest)) {
225                 char *buf;
226                 int result;
227                 size_t restlen = strlen(rest);
228
229                 /* rest must not be empty, or start or end with "/" */
230                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
231                         return 0;
232
233                 /*
234                  * Does the refname try to escape refs/?
235                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
236                  * is not.
237                  */
238                 buf = xmallocz(restlen);
239                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
240                 free(buf);
241                 return result;
242         }
243
244         do {
245                 if (!isupper(*refname) && *refname != '_')
246                         return 0;
247                 refname++;
248         } while (*refname);
249         return 1;
250 }
251
252 /*
253  * Return true if refname, which has the specified oid and flags, can
254  * be resolved to an object in the database. If the referred-to object
255  * does not exist, emit a warning and return false.
256  */
257 int ref_resolves_to_object(const char *refname,
258                            const struct object_id *oid,
259                            unsigned int flags)
260 {
261         if (flags & REF_ISBROKEN)
262                 return 0;
263         if (!has_object_file(oid)) {
264                 error(_("%s does not point to a valid object!"), refname);
265                 return 0;
266         }
267         return 1;
268 }
269
270 char *refs_resolve_refdup(struct ref_store *refs,
271                           const char *refname, int resolve_flags,
272                           struct object_id *oid, int *flags)
273 {
274         const char *result;
275
276         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
277                                          oid, flags);
278         return xstrdup_or_null(result);
279 }
280
281 char *resolve_refdup(const char *refname, int resolve_flags,
282                      struct object_id *oid, int *flags)
283 {
284         return refs_resolve_refdup(get_main_ref_store(the_repository),
285                                    refname, resolve_flags,
286                                    oid, flags);
287 }
288
289 /* The argument to filter_refs */
290 struct ref_filter {
291         const char *pattern;
292         const char *prefix;
293         each_ref_fn *fn;
294         void *cb_data;
295 };
296
297 int refs_read_ref_full(struct ref_store *refs, const char *refname,
298                        int resolve_flags, struct object_id *oid, int *flags)
299 {
300         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, oid, flags))
301                 return 0;
302         return -1;
303 }
304
305 int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
306 {
307         return refs_read_ref_full(get_main_ref_store(the_repository), refname,
308                                   resolve_flags, oid, flags);
309 }
310
311 int read_ref(const char *refname, struct object_id *oid)
312 {
313         return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
314 }
315
316 static int refs_ref_exists(struct ref_store *refs, const char *refname)
317 {
318         return !!refs_resolve_ref_unsafe(refs, refname, RESOLVE_REF_READING, NULL, NULL);
319 }
320
321 int ref_exists(const char *refname)
322 {
323         return refs_ref_exists(get_main_ref_store(the_repository), refname);
324 }
325
326 static int filter_refs(const char *refname, const struct object_id *oid,
327                            int flags, void *data)
328 {
329         struct ref_filter *filter = (struct ref_filter *)data;
330
331         if (wildmatch(filter->pattern, refname, 0))
332                 return 0;
333         if (filter->prefix)
334                 skip_prefix(refname, filter->prefix, &refname);
335         return filter->fn(refname, oid, flags, filter->cb_data);
336 }
337
338 enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
339 {
340         struct object *o = lookup_unknown_object(name);
341
342         if (o->type == OBJ_NONE) {
343                 int type = oid_object_info(the_repository, name, NULL);
344                 if (type < 0 || !object_as_type(o, type, 0))
345                         return PEEL_INVALID;
346         }
347
348         if (o->type != OBJ_TAG)
349                 return PEEL_NON_TAG;
350
351         o = deref_tag_noverify(o);
352         if (!o)
353                 return PEEL_INVALID;
354
355         oidcpy(oid, &o->oid);
356         return PEEL_PEELED;
357 }
358
359 struct warn_if_dangling_data {
360         FILE *fp;
361         const char *refname;
362         const struct string_list *refnames;
363         const char *msg_fmt;
364 };
365
366 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
367                                    int flags, void *cb_data)
368 {
369         struct warn_if_dangling_data *d = cb_data;
370         const char *resolves_to;
371
372         if (!(flags & REF_ISSYMREF))
373                 return 0;
374
375         resolves_to = resolve_ref_unsafe(refname, 0, NULL, NULL);
376         if (!resolves_to
377             || (d->refname
378                 ? strcmp(resolves_to, d->refname)
379                 : !string_list_has_string(d->refnames, resolves_to))) {
380                 return 0;
381         }
382
383         fprintf(d->fp, d->msg_fmt, refname);
384         fputc('\n', d->fp);
385         return 0;
386 }
387
388 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
389 {
390         struct warn_if_dangling_data data;
391
392         data.fp = fp;
393         data.refname = refname;
394         data.refnames = NULL;
395         data.msg_fmt = msg_fmt;
396         for_each_rawref(warn_if_dangling_symref, &data);
397 }
398
399 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
400 {
401         struct warn_if_dangling_data data;
402
403         data.fp = fp;
404         data.refname = NULL;
405         data.refnames = refnames;
406         data.msg_fmt = msg_fmt;
407         for_each_rawref(warn_if_dangling_symref, &data);
408 }
409
410 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
411 {
412         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
413 }
414
415 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
416 {
417         return refs_for_each_tag_ref(get_main_ref_store(the_repository), fn, cb_data);
418 }
419
420 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
421 {
422         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
423 }
424
425 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
426 {
427         return refs_for_each_branch_ref(get_main_ref_store(the_repository), fn, cb_data);
428 }
429
430 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
431 {
432         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
433 }
434
435 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
436 {
437         return refs_for_each_remote_ref(get_main_ref_store(the_repository), fn, cb_data);
438 }
439
440 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
441 {
442         struct strbuf buf = STRBUF_INIT;
443         int ret = 0;
444         struct object_id oid;
445         int flag;
446
447         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
448         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, &oid, &flag))
449                 ret = fn(buf.buf, &oid, flag, cb_data);
450         strbuf_release(&buf);
451
452         return ret;
453 }
454
455 void normalize_glob_ref(struct string_list_item *item, const char *prefix,
456                         const char *pattern)
457 {
458         struct strbuf normalized_pattern = STRBUF_INIT;
459
460         if (*pattern == '/')
461                 BUG("pattern must not start with '/'");
462
463         if (prefix) {
464                 strbuf_addstr(&normalized_pattern, prefix);
465         }
466         else if (!starts_with(pattern, "refs/"))
467                 strbuf_addstr(&normalized_pattern, "refs/");
468         strbuf_addstr(&normalized_pattern, pattern);
469         strbuf_strip_suffix(&normalized_pattern, "/");
470
471         item->string = strbuf_detach(&normalized_pattern, NULL);
472         item->util = has_glob_specials(pattern) ? NULL : item->string;
473         strbuf_release(&normalized_pattern);
474 }
475
476 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
477         const char *prefix, void *cb_data)
478 {
479         struct strbuf real_pattern = STRBUF_INIT;
480         struct ref_filter filter;
481         int ret;
482
483         if (!prefix && !starts_with(pattern, "refs/"))
484                 strbuf_addstr(&real_pattern, "refs/");
485         else if (prefix)
486                 strbuf_addstr(&real_pattern, prefix);
487         strbuf_addstr(&real_pattern, pattern);
488
489         if (!has_glob_specials(pattern)) {
490                 /* Append implied '/' '*' if not present. */
491                 strbuf_complete(&real_pattern, '/');
492                 /* No need to check for '*', there is none. */
493                 strbuf_addch(&real_pattern, '*');
494         }
495
496         filter.pattern = real_pattern.buf;
497         filter.prefix = prefix;
498         filter.fn = fn;
499         filter.cb_data = cb_data;
500         ret = for_each_ref(filter_refs, &filter);
501
502         strbuf_release(&real_pattern);
503         return ret;
504 }
505
506 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
507 {
508         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
509 }
510
511 const char *prettify_refname(const char *name)
512 {
513         if (skip_prefix(name, "refs/heads/", &name) ||
514             skip_prefix(name, "refs/tags/", &name) ||
515             skip_prefix(name, "refs/remotes/", &name))
516                 ; /* nothing */
517         return name;
518 }
519
520 static const char *ref_rev_parse_rules[] = {
521         "%.*s",
522         "refs/%.*s",
523         "refs/tags/%.*s",
524         "refs/heads/%.*s",
525         "refs/remotes/%.*s",
526         "refs/remotes/%.*s/HEAD",
527         NULL
528 };
529
530 #define NUM_REV_PARSE_RULES (ARRAY_SIZE(ref_rev_parse_rules) - 1)
531
532 /*
533  * Is it possible that the caller meant full_name with abbrev_name?
534  * If so return a non-zero value to signal "yes"; the magnitude of
535  * the returned value gives the precedence used for disambiguation.
536  *
537  * If abbrev_name cannot mean full_name, return 0.
538  */
539 int refname_match(const char *abbrev_name, const char *full_name)
540 {
541         const char **p;
542         const int abbrev_name_len = strlen(abbrev_name);
543         const int num_rules = NUM_REV_PARSE_RULES;
544
545         for (p = ref_rev_parse_rules; *p; p++)
546                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name)))
547                         return &ref_rev_parse_rules[num_rules] - p;
548
549         return 0;
550 }
551
552 /*
553  * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
554  * the results to 'prefixes'
555  */
556 void expand_ref_prefix(struct strvec *prefixes, const char *prefix)
557 {
558         const char **p;
559         int len = strlen(prefix);
560
561         for (p = ref_rev_parse_rules; *p; p++)
562                 strvec_pushf(prefixes, *p, len, prefix);
563 }
564
565 char *repo_default_branch_name(struct repository *r)
566 {
567         const char *config_key = "init.defaultbranch";
568         const char *config_display_key = "init.defaultBranch";
569         char *ret = NULL, *full_ref;
570
571         if (repo_config_get_string(r, config_key, &ret) < 0)
572                 die(_("could not retrieve `%s`"), config_display_key);
573
574         if (!ret)
575                 ret = xstrdup("master");
576
577         full_ref = xstrfmt("refs/heads/%s", ret);
578         if (check_refname_format(full_ref, 0))
579                 die(_("invalid branch name: %s = %s"), config_display_key, ret);
580         free(full_ref);
581
582         return ret;
583 }
584
585 const char *git_default_branch_name(void)
586 {
587         static char *ret;
588
589         if (!ret)
590                 ret = repo_default_branch_name(the_repository);
591
592         return ret;
593 }
594
595 /*
596  * *string and *len will only be substituted, and *string returned (for
597  * later free()ing) if the string passed in is a magic short-hand form
598  * to name a branch.
599  */
600 static char *substitute_branch_name(struct repository *r,
601                                     const char **string, int *len)
602 {
603         struct strbuf buf = STRBUF_INIT;
604         int ret = repo_interpret_branch_name(r, *string, *len, &buf, 0);
605
606         if (ret == *len) {
607                 size_t size;
608                 *string = strbuf_detach(&buf, &size);
609                 *len = size;
610                 return (char *)*string;
611         }
612
613         return NULL;
614 }
615
616 int repo_dwim_ref(struct repository *r, const char *str, int len,
617                   struct object_id *oid, char **ref)
618 {
619         char *last_branch = substitute_branch_name(r, &str, &len);
620         int   refs_found  = expand_ref(r, str, len, oid, ref);
621         free(last_branch);
622         return refs_found;
623 }
624
625 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref)
626 {
627         return repo_dwim_ref(the_repository, str, len, oid, ref);
628 }
629
630 int expand_ref(struct repository *repo, const char *str, int len,
631                struct object_id *oid, char **ref)
632 {
633         const char **p, *r;
634         int refs_found = 0;
635         struct strbuf fullref = STRBUF_INIT;
636
637         *ref = NULL;
638         for (p = ref_rev_parse_rules; *p; p++) {
639                 struct object_id oid_from_ref;
640                 struct object_id *this_result;
641                 int flag;
642
643                 this_result = refs_found ? &oid_from_ref : oid;
644                 strbuf_reset(&fullref);
645                 strbuf_addf(&fullref, *p, len, str);
646                 r = refs_resolve_ref_unsafe(get_main_ref_store(repo),
647                                             fullref.buf, RESOLVE_REF_READING,
648                                             this_result, &flag);
649                 if (r) {
650                         if (!refs_found++)
651                                 *ref = xstrdup(r);
652                         if (!warn_ambiguous_refs)
653                                 break;
654                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
655                         warning(_("ignoring dangling symref %s"), fullref.buf);
656                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
657                         warning(_("ignoring broken ref %s"), fullref.buf);
658                 }
659         }
660         strbuf_release(&fullref);
661         return refs_found;
662 }
663
664 int repo_dwim_log(struct repository *r, const char *str, int len,
665                   struct object_id *oid, char **log)
666 {
667         struct ref_store *refs = get_main_ref_store(r);
668         char *last_branch = substitute_branch_name(r, &str, &len);
669         const char **p;
670         int logs_found = 0;
671         struct strbuf path = STRBUF_INIT;
672
673         *log = NULL;
674         for (p = ref_rev_parse_rules; *p; p++) {
675                 struct object_id hash;
676                 const char *ref, *it;
677
678                 strbuf_reset(&path);
679                 strbuf_addf(&path, *p, len, str);
680                 ref = refs_resolve_ref_unsafe(refs, path.buf,
681                                               RESOLVE_REF_READING,
682                                               &hash, NULL);
683                 if (!ref)
684                         continue;
685                 if (refs_reflog_exists(refs, path.buf))
686                         it = path.buf;
687                 else if (strcmp(ref, path.buf) &&
688                          refs_reflog_exists(refs, ref))
689                         it = ref;
690                 else
691                         continue;
692                 if (!logs_found++) {
693                         *log = xstrdup(it);
694                         oidcpy(oid, &hash);
695                 }
696                 if (!warn_ambiguous_refs)
697                         break;
698         }
699         strbuf_release(&path);
700         free(last_branch);
701         return logs_found;
702 }
703
704 int dwim_log(const char *str, int len, struct object_id *oid, char **log)
705 {
706         return repo_dwim_log(the_repository, str, len, oid, log);
707 }
708
709 static int is_per_worktree_ref(const char *refname)
710 {
711         return !strcmp(refname, "HEAD") ||
712                 starts_with(refname, "refs/worktree/") ||
713                 starts_with(refname, "refs/bisect/") ||
714                 starts_with(refname, "refs/rewritten/");
715 }
716
717 static int is_pseudoref_syntax(const char *refname)
718 {
719         const char *c;
720
721         for (c = refname; *c; c++) {
722                 if (!isupper(*c) && *c != '-' && *c != '_')
723                         return 0;
724         }
725
726         return 1;
727 }
728
729 static int is_main_pseudoref_syntax(const char *refname)
730 {
731         return skip_prefix(refname, "main-worktree/", &refname) &&
732                 *refname &&
733                 is_pseudoref_syntax(refname);
734 }
735
736 static int is_other_pseudoref_syntax(const char *refname)
737 {
738         if (!skip_prefix(refname, "worktrees/", &refname))
739                 return 0;
740         refname = strchr(refname, '/');
741         if (!refname || !refname[1])
742                 return 0;
743         return is_pseudoref_syntax(refname + 1);
744 }
745
746 enum ref_type ref_type(const char *refname)
747 {
748         if (is_per_worktree_ref(refname))
749                 return REF_TYPE_PER_WORKTREE;
750         if (is_pseudoref_syntax(refname))
751                 return REF_TYPE_PSEUDOREF;
752         if (is_main_pseudoref_syntax(refname))
753                 return REF_TYPE_MAIN_PSEUDOREF;
754         if (is_other_pseudoref_syntax(refname))
755                 return REF_TYPE_OTHER_PSEUDOREF;
756         return REF_TYPE_NORMAL;
757 }
758
759 long get_files_ref_lock_timeout_ms(void)
760 {
761         static int configured = 0;
762
763         /* The default timeout is 100 ms: */
764         static int timeout_ms = 100;
765
766         if (!configured) {
767                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
768                 configured = 1;
769         }
770
771         return timeout_ms;
772 }
773
774 static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
775                            const struct object_id *old_oid, struct strbuf *err)
776 {
777         const char *filename;
778         int fd;
779         struct lock_file lock = LOCK_INIT;
780         struct strbuf buf = STRBUF_INIT;
781         int ret = -1;
782
783         if (!oid)
784                 return 0;
785
786         strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
787
788         filename = git_path("%s", pseudoref);
789         fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
790                                                get_files_ref_lock_timeout_ms());
791         if (fd < 0) {
792                 strbuf_addf(err, _("could not open '%s' for writing: %s"),
793                             filename, strerror(errno));
794                 goto done;
795         }
796
797         if (old_oid) {
798                 struct object_id actual_old_oid;
799
800                 if (read_ref(pseudoref, &actual_old_oid)) {
801                         if (!is_null_oid(old_oid)) {
802                                 strbuf_addf(err, _("could not read ref '%s'"),
803                                             pseudoref);
804                                 rollback_lock_file(&lock);
805                                 goto done;
806                         }
807                 } else if (is_null_oid(old_oid)) {
808                         strbuf_addf(err, _("ref '%s' already exists"),
809                                     pseudoref);
810                         rollback_lock_file(&lock);
811                         goto done;
812                 } else if (!oideq(&actual_old_oid, old_oid)) {
813                         strbuf_addf(err, _("unexpected object ID when writing '%s'"),
814                                     pseudoref);
815                         rollback_lock_file(&lock);
816                         goto done;
817                 }
818         }
819
820         if (write_in_full(fd, buf.buf, buf.len) < 0) {
821                 strbuf_addf(err, _("could not write to '%s'"), filename);
822                 rollback_lock_file(&lock);
823                 goto done;
824         }
825
826         commit_lock_file(&lock);
827         ret = 0;
828 done:
829         strbuf_release(&buf);
830         return ret;
831 }
832
833 static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
834 {
835         const char *filename;
836
837         filename = git_path("%s", pseudoref);
838
839         if (old_oid && !is_null_oid(old_oid)) {
840                 struct lock_file lock = LOCK_INIT;
841                 int fd;
842                 struct object_id actual_old_oid;
843
844                 fd = hold_lock_file_for_update_timeout(
845                                 &lock, filename, 0,
846                                 get_files_ref_lock_timeout_ms());
847                 if (fd < 0) {
848                         error_errno(_("could not open '%s' for writing"),
849                                     filename);
850                         return -1;
851                 }
852                 if (read_ref(pseudoref, &actual_old_oid))
853                         die(_("could not read ref '%s'"), pseudoref);
854                 if (!oideq(&actual_old_oid, old_oid)) {
855                         error(_("unexpected object ID when deleting '%s'"),
856                               pseudoref);
857                         rollback_lock_file(&lock);
858                         return -1;
859                 }
860
861                 unlink(filename);
862                 rollback_lock_file(&lock);
863         } else {
864                 unlink(filename);
865         }
866
867         return 0;
868 }
869
870 int refs_delete_ref(struct ref_store *refs, const char *msg,
871                     const char *refname,
872                     const struct object_id *old_oid,
873                     unsigned int flags)
874 {
875         struct ref_transaction *transaction;
876         struct strbuf err = STRBUF_INIT;
877
878         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
879                 assert(refs == get_main_ref_store(the_repository));
880                 return delete_pseudoref(refname, old_oid);
881         }
882
883         transaction = ref_store_transaction_begin(refs, &err);
884         if (!transaction ||
885             ref_transaction_delete(transaction, refname, old_oid,
886                                    flags, msg, &err) ||
887             ref_transaction_commit(transaction, &err)) {
888                 error("%s", err.buf);
889                 ref_transaction_free(transaction);
890                 strbuf_release(&err);
891                 return 1;
892         }
893         ref_transaction_free(transaction);
894         strbuf_release(&err);
895         return 0;
896 }
897
898 int delete_ref(const char *msg, const char *refname,
899                const struct object_id *old_oid, unsigned int flags)
900 {
901         return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
902                                old_oid, flags);
903 }
904
905 static void copy_reflog_msg(struct strbuf *sb, const char *msg)
906 {
907         char c;
908         int wasspace = 1;
909
910         while ((c = *msg++)) {
911                 if (wasspace && isspace(c))
912                         continue;
913                 wasspace = isspace(c);
914                 if (wasspace)
915                         c = ' ';
916                 strbuf_addch(sb, c);
917         }
918         strbuf_rtrim(sb);
919 }
920
921 static char *normalize_reflog_message(const char *msg)
922 {
923         struct strbuf sb = STRBUF_INIT;
924
925         if (msg && *msg)
926                 copy_reflog_msg(&sb, msg);
927         return strbuf_detach(&sb, NULL);
928 }
929
930 int should_autocreate_reflog(const char *refname)
931 {
932         switch (log_all_ref_updates) {
933         case LOG_REFS_ALWAYS:
934                 return 1;
935         case LOG_REFS_NORMAL:
936                 return starts_with(refname, "refs/heads/") ||
937                         starts_with(refname, "refs/remotes/") ||
938                         starts_with(refname, "refs/notes/") ||
939                         !strcmp(refname, "HEAD");
940         default:
941                 return 0;
942         }
943 }
944
945 int is_branch(const char *refname)
946 {
947         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
948 }
949
950 struct read_ref_at_cb {
951         const char *refname;
952         timestamp_t at_time;
953         int cnt;
954         int reccnt;
955         struct object_id *oid;
956         int found_it;
957
958         struct object_id ooid;
959         struct object_id noid;
960         int tz;
961         timestamp_t date;
962         char **msg;
963         timestamp_t *cutoff_time;
964         int *cutoff_tz;
965         int *cutoff_cnt;
966 };
967
968 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
969                 const char *email, timestamp_t timestamp, int tz,
970                 const char *message, void *cb_data)
971 {
972         struct read_ref_at_cb *cb = cb_data;
973
974         cb->reccnt++;
975         cb->tz = tz;
976         cb->date = timestamp;
977
978         if (timestamp <= cb->at_time || cb->cnt == 0) {
979                 if (cb->msg)
980                         *cb->msg = xstrdup(message);
981                 if (cb->cutoff_time)
982                         *cb->cutoff_time = timestamp;
983                 if (cb->cutoff_tz)
984                         *cb->cutoff_tz = tz;
985                 if (cb->cutoff_cnt)
986                         *cb->cutoff_cnt = cb->reccnt - 1;
987                 /*
988                  * we have not yet updated cb->[n|o]oid so they still
989                  * hold the values for the previous record.
990                  */
991                 if (!is_null_oid(&cb->ooid)) {
992                         oidcpy(cb->oid, noid);
993                         if (!oideq(&cb->ooid, noid))
994                                 warning(_("log for ref %s has gap after %s"),
995                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
996                 }
997                 else if (cb->date == cb->at_time)
998                         oidcpy(cb->oid, noid);
999                 else if (!oideq(noid, cb->oid))
1000                         warning(_("log for ref %s unexpectedly ended on %s"),
1001                                 cb->refname, show_date(cb->date, cb->tz,
1002                                                        DATE_MODE(RFC2822)));
1003                 oidcpy(&cb->ooid, ooid);
1004                 oidcpy(&cb->noid, noid);
1005                 cb->found_it = 1;
1006                 return 1;
1007         }
1008         oidcpy(&cb->ooid, ooid);
1009         oidcpy(&cb->noid, noid);
1010         if (cb->cnt > 0)
1011                 cb->cnt--;
1012         return 0;
1013 }
1014
1015 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
1016                                   const char *email, timestamp_t timestamp,
1017                                   int tz, const char *message, void *cb_data)
1018 {
1019         struct read_ref_at_cb *cb = cb_data;
1020
1021         if (cb->msg)
1022                 *cb->msg = xstrdup(message);
1023         if (cb->cutoff_time)
1024                 *cb->cutoff_time = timestamp;
1025         if (cb->cutoff_tz)
1026                 *cb->cutoff_tz = tz;
1027         if (cb->cutoff_cnt)
1028                 *cb->cutoff_cnt = cb->reccnt;
1029         oidcpy(cb->oid, ooid);
1030         if (is_null_oid(cb->oid))
1031                 oidcpy(cb->oid, noid);
1032         /* We just want the first entry */
1033         return 1;
1034 }
1035
1036 int read_ref_at(struct ref_store *refs, const char *refname,
1037                 unsigned int flags, timestamp_t at_time, int cnt,
1038                 struct object_id *oid, char **msg,
1039                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1040 {
1041         struct read_ref_at_cb cb;
1042
1043         memset(&cb, 0, sizeof(cb));
1044         cb.refname = refname;
1045         cb.at_time = at_time;
1046         cb.cnt = cnt;
1047         cb.msg = msg;
1048         cb.cutoff_time = cutoff_time;
1049         cb.cutoff_tz = cutoff_tz;
1050         cb.cutoff_cnt = cutoff_cnt;
1051         cb.oid = oid;
1052
1053         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
1054
1055         if (!cb.reccnt) {
1056                 if (flags & GET_OID_QUIETLY)
1057                         exit(128);
1058                 else
1059                         die(_("log for %s is empty"), refname);
1060         }
1061         if (cb.found_it)
1062                 return 0;
1063
1064         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
1065
1066         return 1;
1067 }
1068
1069 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
1070                                                     struct strbuf *err)
1071 {
1072         struct ref_transaction *tr;
1073         assert(err);
1074
1075         tr = xcalloc(1, sizeof(struct ref_transaction));
1076         tr->ref_store = refs;
1077         return tr;
1078 }
1079
1080 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
1081 {
1082         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
1083 }
1084
1085 void ref_transaction_free(struct ref_transaction *transaction)
1086 {
1087         size_t i;
1088
1089         if (!transaction)
1090                 return;
1091
1092         switch (transaction->state) {
1093         case REF_TRANSACTION_OPEN:
1094         case REF_TRANSACTION_CLOSED:
1095                 /* OK */
1096                 break;
1097         case REF_TRANSACTION_PREPARED:
1098                 BUG("free called on a prepared reference transaction");
1099                 break;
1100         default:
1101                 BUG("unexpected reference transaction state");
1102                 break;
1103         }
1104
1105         for (i = 0; i < transaction->nr; i++) {
1106                 free(transaction->updates[i]->msg);
1107                 free(transaction->updates[i]);
1108         }
1109         free(transaction->updates);
1110         free(transaction);
1111 }
1112
1113 struct ref_update *ref_transaction_add_update(
1114                 struct ref_transaction *transaction,
1115                 const char *refname, unsigned int flags,
1116                 const struct object_id *new_oid,
1117                 const struct object_id *old_oid,
1118                 const char *msg)
1119 {
1120         struct ref_update *update;
1121
1122         if (transaction->state != REF_TRANSACTION_OPEN)
1123                 BUG("update called for transaction that is not open");
1124
1125         FLEX_ALLOC_STR(update, refname, refname);
1126         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1127         transaction->updates[transaction->nr++] = update;
1128
1129         update->flags = flags;
1130
1131         if (flags & REF_HAVE_NEW)
1132                 oidcpy(&update->new_oid, new_oid);
1133         if (flags & REF_HAVE_OLD)
1134                 oidcpy(&update->old_oid, old_oid);
1135         update->msg = normalize_reflog_message(msg);
1136         return update;
1137 }
1138
1139 int ref_transaction_update(struct ref_transaction *transaction,
1140                            const char *refname,
1141                            const struct object_id *new_oid,
1142                            const struct object_id *old_oid,
1143                            unsigned int flags, const char *msg,
1144                            struct strbuf *err)
1145 {
1146         assert(err);
1147
1148         if ((new_oid && !is_null_oid(new_oid)) ?
1149             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1150             !refname_is_safe(refname)) {
1151                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1152                             refname);
1153                 return -1;
1154         }
1155
1156         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1157                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1158
1159         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1160
1161         ref_transaction_add_update(transaction, refname, flags,
1162                                    new_oid, old_oid, msg);
1163         return 0;
1164 }
1165
1166 int ref_transaction_create(struct ref_transaction *transaction,
1167                            const char *refname,
1168                            const struct object_id *new_oid,
1169                            unsigned int flags, const char *msg,
1170                            struct strbuf *err)
1171 {
1172         if (!new_oid || is_null_oid(new_oid))
1173                 BUG("create called without valid new_oid");
1174         return ref_transaction_update(transaction, refname, new_oid,
1175                                       &null_oid, flags, msg, err);
1176 }
1177
1178 int ref_transaction_delete(struct ref_transaction *transaction,
1179                            const char *refname,
1180                            const struct object_id *old_oid,
1181                            unsigned int flags, const char *msg,
1182                            struct strbuf *err)
1183 {
1184         if (old_oid && is_null_oid(old_oid))
1185                 BUG("delete called with old_oid set to zeros");
1186         return ref_transaction_update(transaction, refname,
1187                                       &null_oid, old_oid,
1188                                       flags, msg, err);
1189 }
1190
1191 int ref_transaction_verify(struct ref_transaction *transaction,
1192                            const char *refname,
1193                            const struct object_id *old_oid,
1194                            unsigned int flags,
1195                            struct strbuf *err)
1196 {
1197         if (!old_oid)
1198                 BUG("verify called with old_oid set to NULL");
1199         return ref_transaction_update(transaction, refname,
1200                                       NULL, old_oid,
1201                                       flags, NULL, err);
1202 }
1203
1204 int refs_update_ref(struct ref_store *refs, const char *msg,
1205                     const char *refname, const struct object_id *new_oid,
1206                     const struct object_id *old_oid, unsigned int flags,
1207                     enum action_on_err onerr)
1208 {
1209         struct ref_transaction *t = NULL;
1210         struct strbuf err = STRBUF_INIT;
1211         int ret = 0;
1212
1213         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
1214                 assert(refs == get_main_ref_store(the_repository));
1215                 ret = write_pseudoref(refname, new_oid, old_oid, &err);
1216         } else {
1217                 t = ref_store_transaction_begin(refs, &err);
1218                 if (!t ||
1219                     ref_transaction_update(t, refname, new_oid, old_oid,
1220                                            flags, msg, &err) ||
1221                     ref_transaction_commit(t, &err)) {
1222                         ret = 1;
1223                         ref_transaction_free(t);
1224                 }
1225         }
1226         if (ret) {
1227                 const char *str = _("update_ref failed for ref '%s': %s");
1228
1229                 switch (onerr) {
1230                 case UPDATE_REFS_MSG_ON_ERR:
1231                         error(str, refname, err.buf);
1232                         break;
1233                 case UPDATE_REFS_DIE_ON_ERR:
1234                         die(str, refname, err.buf);
1235                         break;
1236                 case UPDATE_REFS_QUIET_ON_ERR:
1237                         break;
1238                 }
1239                 strbuf_release(&err);
1240                 return 1;
1241         }
1242         strbuf_release(&err);
1243         if (t)
1244                 ref_transaction_free(t);
1245         return 0;
1246 }
1247
1248 int update_ref(const char *msg, const char *refname,
1249                const struct object_id *new_oid,
1250                const struct object_id *old_oid,
1251                unsigned int flags, enum action_on_err onerr)
1252 {
1253         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1254                                old_oid, flags, onerr);
1255 }
1256
1257 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1258                                    const char *refname, int strict)
1259 {
1260         int i;
1261         static char **scanf_fmts;
1262         static int nr_rules;
1263         char *short_name;
1264         struct strbuf resolved_buf = STRBUF_INIT;
1265
1266         if (!nr_rules) {
1267                 /*
1268                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1269                  * Generate a format suitable for scanf from a
1270                  * ref_rev_parse_rules rule by interpolating "%s" at the
1271                  * location of the "%.*s".
1272                  */
1273                 size_t total_len = 0;
1274                 size_t offset = 0;
1275
1276                 /* the rule list is NULL terminated, count them first */
1277                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1278                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1279                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1280
1281                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1282
1283                 offset = 0;
1284                 for (i = 0; i < nr_rules; i++) {
1285                         assert(offset < total_len);
1286                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1287                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1288                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1289                 }
1290         }
1291
1292         /* bail out if there are no rules */
1293         if (!nr_rules)
1294                 return xstrdup(refname);
1295
1296         /* buffer for scanf result, at most refname must fit */
1297         short_name = xstrdup(refname);
1298
1299         /* skip first rule, it will always match */
1300         for (i = nr_rules - 1; i > 0 ; --i) {
1301                 int j;
1302                 int rules_to_fail = i;
1303                 int short_name_len;
1304
1305                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1306                         continue;
1307
1308                 short_name_len = strlen(short_name);
1309
1310                 /*
1311                  * in strict mode, all (except the matched one) rules
1312                  * must fail to resolve to a valid non-ambiguous ref
1313                  */
1314                 if (strict)
1315                         rules_to_fail = nr_rules;
1316
1317                 /*
1318                  * check if the short name resolves to a valid ref,
1319                  * but use only rules prior to the matched one
1320                  */
1321                 for (j = 0; j < rules_to_fail; j++) {
1322                         const char *rule = ref_rev_parse_rules[j];
1323
1324                         /* skip matched rule */
1325                         if (i == j)
1326                                 continue;
1327
1328                         /*
1329                          * the short name is ambiguous, if it resolves
1330                          * (with this previous rule) to a valid ref
1331                          * read_ref() returns 0 on success
1332                          */
1333                         strbuf_reset(&resolved_buf);
1334                         strbuf_addf(&resolved_buf, rule,
1335                                     short_name_len, short_name);
1336                         if (refs_ref_exists(refs, resolved_buf.buf))
1337                                 break;
1338                 }
1339
1340                 /*
1341                  * short name is non-ambiguous if all previous rules
1342                  * haven't resolved to a valid ref
1343                  */
1344                 if (j == rules_to_fail) {
1345                         strbuf_release(&resolved_buf);
1346                         return short_name;
1347                 }
1348         }
1349
1350         strbuf_release(&resolved_buf);
1351         free(short_name);
1352         return xstrdup(refname);
1353 }
1354
1355 char *shorten_unambiguous_ref(const char *refname, int strict)
1356 {
1357         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1358                                             refname, strict);
1359 }
1360
1361 static struct string_list *hide_refs;
1362
1363 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1364 {
1365         const char *key;
1366         if (!strcmp("transfer.hiderefs", var) ||
1367             (!parse_config_key(var, section, NULL, NULL, &key) &&
1368              !strcmp(key, "hiderefs"))) {
1369                 char *ref;
1370                 int len;
1371
1372                 if (!value)
1373                         return config_error_nonbool(var);
1374                 ref = xstrdup(value);
1375                 len = strlen(ref);
1376                 while (len && ref[len - 1] == '/')
1377                         ref[--len] = '\0';
1378                 if (!hide_refs) {
1379                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1380                         hide_refs->strdup_strings = 1;
1381                 }
1382                 string_list_append(hide_refs, ref);
1383         }
1384         return 0;
1385 }
1386
1387 int ref_is_hidden(const char *refname, const char *refname_full)
1388 {
1389         int i;
1390
1391         if (!hide_refs)
1392                 return 0;
1393         for (i = hide_refs->nr - 1; i >= 0; i--) {
1394                 const char *match = hide_refs->items[i].string;
1395                 const char *subject;
1396                 int neg = 0;
1397                 const char *p;
1398
1399                 if (*match == '!') {
1400                         neg = 1;
1401                         match++;
1402                 }
1403
1404                 if (*match == '^') {
1405                         subject = refname_full;
1406                         match++;
1407                 } else {
1408                         subject = refname;
1409                 }
1410
1411                 /* refname can be NULL when namespaces are used. */
1412                 if (subject &&
1413                     skip_prefix(subject, match, &p) &&
1414                     (!*p || *p == '/'))
1415                         return !neg;
1416         }
1417         return 0;
1418 }
1419
1420 const char *find_descendant_ref(const char *dirname,
1421                                 const struct string_list *extras,
1422                                 const struct string_list *skip)
1423 {
1424         int pos;
1425
1426         if (!extras)
1427                 return NULL;
1428
1429         /*
1430          * Look at the place where dirname would be inserted into
1431          * extras. If there is an entry at that position that starts
1432          * with dirname (remember, dirname includes the trailing
1433          * slash) and is not in skip, then we have a conflict.
1434          */
1435         for (pos = string_list_find_insert_index(extras, dirname, 0);
1436              pos < extras->nr; pos++) {
1437                 const char *extra_refname = extras->items[pos].string;
1438
1439                 if (!starts_with(extra_refname, dirname))
1440                         break;
1441
1442                 if (!skip || !string_list_has_string(skip, extra_refname))
1443                         return extra_refname;
1444         }
1445         return NULL;
1446 }
1447
1448 int refs_rename_ref_available(struct ref_store *refs,
1449                               const char *old_refname,
1450                               const char *new_refname)
1451 {
1452         struct string_list skip = STRING_LIST_INIT_NODUP;
1453         struct strbuf err = STRBUF_INIT;
1454         int ok;
1455
1456         string_list_insert(&skip, old_refname);
1457         ok = !refs_verify_refname_available(refs, new_refname,
1458                                             NULL, &skip, &err);
1459         if (!ok)
1460                 error("%s", err.buf);
1461
1462         string_list_clear(&skip, 0);
1463         strbuf_release(&err);
1464         return ok;
1465 }
1466
1467 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1468 {
1469         struct object_id oid;
1470         int flag;
1471
1472         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1473                                 &oid, &flag))
1474                 return fn("HEAD", &oid, flag, cb_data);
1475
1476         return 0;
1477 }
1478
1479 int head_ref(each_ref_fn fn, void *cb_data)
1480 {
1481         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1482 }
1483
1484 struct ref_iterator *refs_ref_iterator_begin(
1485                 struct ref_store *refs,
1486                 const char *prefix, int trim, int flags)
1487 {
1488         struct ref_iterator *iter;
1489
1490         if (ref_paranoia < 0)
1491                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1492         if (ref_paranoia)
1493                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1494
1495         iter = refs->be->iterator_begin(refs, prefix, flags);
1496
1497         /*
1498          * `iterator_begin()` already takes care of prefix, but we
1499          * might need to do some trimming:
1500          */
1501         if (trim)
1502                 iter = prefix_ref_iterator_begin(iter, "", trim);
1503
1504         /* Sanity check for subclasses: */
1505         if (!iter->ordered)
1506                 BUG("reference iterator is not ordered");
1507
1508         return iter;
1509 }
1510
1511 /*
1512  * Call fn for each reference in the specified submodule for which the
1513  * refname begins with prefix. If trim is non-zero, then trim that
1514  * many characters off the beginning of each refname before passing
1515  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1516  * include broken references in the iteration. If fn ever returns a
1517  * non-zero value, stop the iteration and return that value;
1518  * otherwise, return 0.
1519  */
1520 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1521                                 each_repo_ref_fn fn, int trim, int flags,
1522                                 void *cb_data)
1523 {
1524         struct ref_iterator *iter;
1525         struct ref_store *refs = get_main_ref_store(r);
1526
1527         if (!refs)
1528                 return 0;
1529
1530         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1531
1532         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1533 }
1534
1535 struct do_for_each_ref_help {
1536         each_ref_fn *fn;
1537         void *cb_data;
1538 };
1539
1540 static int do_for_each_ref_helper(struct repository *r,
1541                                   const char *refname,
1542                                   const struct object_id *oid,
1543                                   int flags,
1544                                   void *cb_data)
1545 {
1546         struct do_for_each_ref_help *hp = cb_data;
1547
1548         return hp->fn(refname, oid, flags, hp->cb_data);
1549 }
1550
1551 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1552                            each_ref_fn fn, int trim, int flags, void *cb_data)
1553 {
1554         struct ref_iterator *iter;
1555         struct do_for_each_ref_help hp = { fn, cb_data };
1556
1557         if (!refs)
1558                 return 0;
1559
1560         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1561
1562         return do_for_each_repo_ref_iterator(the_repository, iter,
1563                                         do_for_each_ref_helper, &hp);
1564 }
1565
1566 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1567 {
1568         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1569 }
1570
1571 int for_each_ref(each_ref_fn fn, void *cb_data)
1572 {
1573         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1574 }
1575
1576 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1577                          each_ref_fn fn, void *cb_data)
1578 {
1579         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1580 }
1581
1582 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1583 {
1584         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1585 }
1586
1587 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1588 {
1589         unsigned int flag = 0;
1590
1591         if (broken)
1592                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1593         return do_for_each_ref(get_main_ref_store(the_repository),
1594                                prefix, fn, 0, flag, cb_data);
1595 }
1596
1597 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1598                              each_ref_fn fn, void *cb_data,
1599                              unsigned int broken)
1600 {
1601         unsigned int flag = 0;
1602
1603         if (broken)
1604                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1605         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1606 }
1607
1608 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1609 {
1610         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1611                                     strlen(git_replace_ref_base),
1612                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1613 }
1614
1615 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1616 {
1617         struct strbuf buf = STRBUF_INIT;
1618         int ret;
1619         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1620         ret = do_for_each_ref(get_main_ref_store(the_repository),
1621                               buf.buf, fn, 0, 0, cb_data);
1622         strbuf_release(&buf);
1623         return ret;
1624 }
1625
1626 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1627 {
1628         return do_for_each_ref(refs, "", fn, 0,
1629                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1630 }
1631
1632 int for_each_rawref(each_ref_fn fn, void *cb_data)
1633 {
1634         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1635 }
1636
1637 int refs_read_raw_ref(struct ref_store *ref_store,
1638                       const char *refname, struct object_id *oid,
1639                       struct strbuf *referent, unsigned int *type)
1640 {
1641         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
1642 }
1643
1644 /* This function needs to return a meaningful errno on failure */
1645 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1646                                     const char *refname,
1647                                     int resolve_flags,
1648                                     struct object_id *oid, int *flags)
1649 {
1650         static struct strbuf sb_refname = STRBUF_INIT;
1651         struct object_id unused_oid;
1652         int unused_flags;
1653         int symref_count;
1654
1655         if (!oid)
1656                 oid = &unused_oid;
1657         if (!flags)
1658                 flags = &unused_flags;
1659
1660         *flags = 0;
1661
1662         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1663                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1664                     !refname_is_safe(refname)) {
1665                         errno = EINVAL;
1666                         return NULL;
1667                 }
1668
1669                 /*
1670                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1671                  * missing refs and refs that were present but invalid,
1672                  * to complain about the latter to stderr.
1673                  *
1674                  * We don't know whether the ref exists, so don't set
1675                  * REF_ISBROKEN yet.
1676                  */
1677                 *flags |= REF_BAD_NAME;
1678         }
1679
1680         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1681                 unsigned int read_flags = 0;
1682
1683                 if (refs_read_raw_ref(refs, refname,
1684                                       oid, &sb_refname, &read_flags)) {
1685                         *flags |= read_flags;
1686
1687                         /* In reading mode, refs must eventually resolve */
1688                         if (resolve_flags & RESOLVE_REF_READING)
1689                                 return NULL;
1690
1691                         /*
1692                          * Otherwise a missing ref is OK. But the files backend
1693                          * may show errors besides ENOENT if there are
1694                          * similarly-named refs.
1695                          */
1696                         if (errno != ENOENT &&
1697                             errno != EISDIR &&
1698                             errno != ENOTDIR)
1699                                 return NULL;
1700
1701                         oidclr(oid);
1702                         if (*flags & REF_BAD_NAME)
1703                                 *flags |= REF_ISBROKEN;
1704                         return refname;
1705                 }
1706
1707                 *flags |= read_flags;
1708
1709                 if (!(read_flags & REF_ISSYMREF)) {
1710                         if (*flags & REF_BAD_NAME) {
1711                                 oidclr(oid);
1712                                 *flags |= REF_ISBROKEN;
1713                         }
1714                         return refname;
1715                 }
1716
1717                 refname = sb_refname.buf;
1718                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1719                         oidclr(oid);
1720                         return refname;
1721                 }
1722                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1723                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1724                             !refname_is_safe(refname)) {
1725                                 errno = EINVAL;
1726                                 return NULL;
1727                         }
1728
1729                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1730                 }
1731         }
1732
1733         errno = ELOOP;
1734         return NULL;
1735 }
1736
1737 /* backend functions */
1738 int refs_init_db(struct strbuf *err)
1739 {
1740         struct ref_store *refs = get_main_ref_store(the_repository);
1741
1742         return refs->be->init_db(refs, err);
1743 }
1744
1745 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1746                                struct object_id *oid, int *flags)
1747 {
1748         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1749                                        resolve_flags, oid, flags);
1750 }
1751
1752 int resolve_gitlink_ref(const char *submodule, const char *refname,
1753                         struct object_id *oid)
1754 {
1755         struct ref_store *refs;
1756         int flags;
1757
1758         refs = get_submodule_ref_store(submodule);
1759
1760         if (!refs)
1761                 return -1;
1762
1763         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1764             is_null_oid(oid))
1765                 return -1;
1766         return 0;
1767 }
1768
1769 struct ref_store_hash_entry
1770 {
1771         struct hashmap_entry ent;
1772
1773         struct ref_store *refs;
1774
1775         /* NUL-terminated identifier of the ref store: */
1776         char name[FLEX_ARRAY];
1777 };
1778
1779 static int ref_store_hash_cmp(const void *unused_cmp_data,
1780                               const struct hashmap_entry *eptr,
1781                               const struct hashmap_entry *entry_or_key,
1782                               const void *keydata)
1783 {
1784         const struct ref_store_hash_entry *e1, *e2;
1785         const char *name;
1786
1787         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1788         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1789         name = keydata ? keydata : e2->name;
1790
1791         return strcmp(e1->name, name);
1792 }
1793
1794 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1795                 const char *name, struct ref_store *refs)
1796 {
1797         struct ref_store_hash_entry *entry;
1798
1799         FLEX_ALLOC_STR(entry, name, name);
1800         hashmap_entry_init(&entry->ent, strhash(name));
1801         entry->refs = refs;
1802         return entry;
1803 }
1804
1805 /* A hashmap of ref_stores, stored by submodule name: */
1806 static struct hashmap submodule_ref_stores;
1807
1808 /* A hashmap of ref_stores, stored by worktree id: */
1809 static struct hashmap worktree_ref_stores;
1810
1811 /*
1812  * Look up a ref store by name. If that ref_store hasn't been
1813  * registered yet, return NULL.
1814  */
1815 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1816                                               const char *name)
1817 {
1818         struct ref_store_hash_entry *entry;
1819         unsigned int hash;
1820
1821         if (!map->tablesize)
1822                 /* It's initialized on demand in register_ref_store(). */
1823                 return NULL;
1824
1825         hash = strhash(name);
1826         entry = hashmap_get_entry_from_hash(map, hash, name,
1827                                         struct ref_store_hash_entry, ent);
1828         return entry ? entry->refs : NULL;
1829 }
1830
1831 /*
1832  * Create, record, and return a ref_store instance for the specified
1833  * gitdir.
1834  */
1835 static struct ref_store *ref_store_init(const char *gitdir,
1836                                         unsigned int flags)
1837 {
1838         const char *be_name = "files";
1839         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1840         struct ref_store *refs;
1841
1842         if (!be)
1843                 BUG("reference backend %s is unknown", be_name);
1844
1845         refs = be->init(gitdir, flags);
1846         return refs;
1847 }
1848
1849 struct ref_store *get_main_ref_store(struct repository *r)
1850 {
1851         if (r->refs_private)
1852                 return r->refs_private;
1853
1854         if (!r->gitdir)
1855                 BUG("attempting to get main_ref_store outside of repository");
1856
1857         r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1858         return r->refs_private;
1859 }
1860
1861 /*
1862  * Associate a ref store with a name. It is a fatal error to call this
1863  * function twice for the same name.
1864  */
1865 static void register_ref_store_map(struct hashmap *map,
1866                                    const char *type,
1867                                    struct ref_store *refs,
1868                                    const char *name)
1869 {
1870         struct ref_store_hash_entry *entry;
1871
1872         if (!map->tablesize)
1873                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1874
1875         entry = alloc_ref_store_hash_entry(name, refs);
1876         if (hashmap_put(map, &entry->ent))
1877                 BUG("%s ref_store '%s' initialized twice", type, name);
1878 }
1879
1880 struct ref_store *get_submodule_ref_store(const char *submodule)
1881 {
1882         struct strbuf submodule_sb = STRBUF_INIT;
1883         struct ref_store *refs;
1884         char *to_free = NULL;
1885         size_t len;
1886
1887         if (!submodule)
1888                 return NULL;
1889
1890         len = strlen(submodule);
1891         while (len && is_dir_sep(submodule[len - 1]))
1892                 len--;
1893         if (!len)
1894                 return NULL;
1895
1896         if (submodule[len])
1897                 /* We need to strip off one or more trailing slashes */
1898                 submodule = to_free = xmemdupz(submodule, len);
1899
1900         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1901         if (refs)
1902                 goto done;
1903
1904         strbuf_addstr(&submodule_sb, submodule);
1905         if (!is_nonbare_repository_dir(&submodule_sb))
1906                 goto done;
1907
1908         if (submodule_to_gitdir(&submodule_sb, submodule))
1909                 goto done;
1910
1911         /* assume that add_submodule_odb() has been called */
1912         refs = ref_store_init(submodule_sb.buf,
1913                               REF_STORE_READ | REF_STORE_ODB);
1914         register_ref_store_map(&submodule_ref_stores, "submodule",
1915                                refs, submodule);
1916
1917 done:
1918         strbuf_release(&submodule_sb);
1919         free(to_free);
1920
1921         return refs;
1922 }
1923
1924 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1925 {
1926         struct ref_store *refs;
1927         const char *id;
1928
1929         if (wt->is_current)
1930                 return get_main_ref_store(the_repository);
1931
1932         id = wt->id ? wt->id : "/";
1933         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1934         if (refs)
1935                 return refs;
1936
1937         if (wt->id)
1938                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1939                                       REF_STORE_ALL_CAPS);
1940         else
1941                 refs = ref_store_init(get_git_common_dir(),
1942                                       REF_STORE_ALL_CAPS);
1943
1944         if (refs)
1945                 register_ref_store_map(&worktree_ref_stores, "worktree",
1946                                        refs, id);
1947         return refs;
1948 }
1949
1950 void base_ref_store_init(struct ref_store *refs,
1951                          const struct ref_storage_be *be)
1952 {
1953         refs->be = be;
1954 }
1955
1956 /* backend functions */
1957 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1958 {
1959         return refs->be->pack_refs(refs, flags);
1960 }
1961
1962 int refs_peel_ref(struct ref_store *refs, const char *refname,
1963                   struct object_id *oid)
1964 {
1965         int flag;
1966         struct object_id base;
1967
1968         if (current_ref_iter && current_ref_iter->refname == refname) {
1969                 struct object_id peeled;
1970
1971                 if (ref_iterator_peel(current_ref_iter, &peeled))
1972                         return -1;
1973                 oidcpy(oid, &peeled);
1974                 return 0;
1975         }
1976
1977         if (refs_read_ref_full(refs, refname,
1978                                RESOLVE_REF_READING, &base, &flag))
1979                 return -1;
1980
1981         return peel_object(&base, oid);
1982 }
1983
1984 int peel_ref(const char *refname, struct object_id *oid)
1985 {
1986         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1987 }
1988
1989 int refs_create_symref(struct ref_store *refs,
1990                        const char *ref_target,
1991                        const char *refs_heads_master,
1992                        const char *logmsg)
1993 {
1994         char *msg;
1995         int retval;
1996
1997         msg = normalize_reflog_message(logmsg);
1998         retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
1999                                          msg);
2000         free(msg);
2001         return retval;
2002 }
2003
2004 int create_symref(const char *ref_target, const char *refs_heads_master,
2005                   const char *logmsg)
2006 {
2007         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
2008                                   refs_heads_master, logmsg);
2009 }
2010
2011 int ref_update_reject_duplicates(struct string_list *refnames,
2012                                  struct strbuf *err)
2013 {
2014         size_t i, n = refnames->nr;
2015
2016         assert(err);
2017
2018         for (i = 1; i < n; i++) {
2019                 int cmp = strcmp(refnames->items[i - 1].string,
2020                                  refnames->items[i].string);
2021
2022                 if (!cmp) {
2023                         strbuf_addf(err,
2024                                     _("multiple updates for ref '%s' not allowed"),
2025                                     refnames->items[i].string);
2026                         return 1;
2027                 } else if (cmp > 0) {
2028                         BUG("ref_update_reject_duplicates() received unsorted list");
2029                 }
2030         }
2031         return 0;
2032 }
2033
2034 static const char hook_not_found;
2035 static const char *hook;
2036
2037 static int run_transaction_hook(struct ref_transaction *transaction,
2038                                 const char *state)
2039 {
2040         struct child_process proc = CHILD_PROCESS_INIT;
2041         struct strbuf buf = STRBUF_INIT;
2042         int ret = 0, i;
2043
2044         if (hook == &hook_not_found)
2045                 return ret;
2046         if (!hook)
2047                 hook = xstrdup_or_null(find_hook("reference-transaction"));
2048         if (!hook) {
2049                 hook = &hook_not_found;
2050                 return ret;
2051         }
2052
2053         strvec_pushl(&proc.args, hook, state, NULL);
2054         proc.in = -1;
2055         proc.stdout_to_stderr = 1;
2056         proc.trace2_hook_name = "reference-transaction";
2057
2058         ret = start_command(&proc);
2059         if (ret)
2060                 return ret;
2061
2062         sigchain_push(SIGPIPE, SIG_IGN);
2063
2064         for (i = 0; i < transaction->nr; i++) {
2065                 struct ref_update *update = transaction->updates[i];
2066
2067                 strbuf_reset(&buf);
2068                 strbuf_addf(&buf, "%s %s %s\n",
2069                             oid_to_hex(&update->old_oid),
2070                             oid_to_hex(&update->new_oid),
2071                             update->refname);
2072
2073                 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
2074                         if (errno != EPIPE)
2075                                 ret = -1;
2076                         break;
2077                 }
2078         }
2079
2080         close(proc.in);
2081         sigchain_pop(SIGPIPE);
2082         strbuf_release(&buf);
2083
2084         ret |= finish_command(&proc);
2085         return ret;
2086 }
2087
2088 int ref_transaction_prepare(struct ref_transaction *transaction,
2089                             struct strbuf *err)
2090 {
2091         struct ref_store *refs = transaction->ref_store;
2092         int ret;
2093
2094         switch (transaction->state) {
2095         case REF_TRANSACTION_OPEN:
2096                 /* Good. */
2097                 break;
2098         case REF_TRANSACTION_PREPARED:
2099                 BUG("prepare called twice on reference transaction");
2100                 break;
2101         case REF_TRANSACTION_CLOSED:
2102                 BUG("prepare called on a closed reference transaction");
2103                 break;
2104         default:
2105                 BUG("unexpected reference transaction state");
2106                 break;
2107         }
2108
2109         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2110                 strbuf_addstr(err,
2111                               _("ref updates forbidden inside quarantine environment"));
2112                 return -1;
2113         }
2114
2115         ret = refs->be->transaction_prepare(refs, transaction, err);
2116         if (ret)
2117                 return ret;
2118
2119         ret = run_transaction_hook(transaction, "prepared");
2120         if (ret) {
2121                 ref_transaction_abort(transaction, err);
2122                 die(_("ref updates aborted by hook"));
2123         }
2124
2125         return 0;
2126 }
2127
2128 int ref_transaction_abort(struct ref_transaction *transaction,
2129                           struct strbuf *err)
2130 {
2131         struct ref_store *refs = transaction->ref_store;
2132         int ret = 0;
2133
2134         switch (transaction->state) {
2135         case REF_TRANSACTION_OPEN:
2136                 /* No need to abort explicitly. */
2137                 break;
2138         case REF_TRANSACTION_PREPARED:
2139                 ret = refs->be->transaction_abort(refs, transaction, err);
2140                 break;
2141         case REF_TRANSACTION_CLOSED:
2142                 BUG("abort called on a closed reference transaction");
2143                 break;
2144         default:
2145                 BUG("unexpected reference transaction state");
2146                 break;
2147         }
2148
2149         run_transaction_hook(transaction, "aborted");
2150
2151         ref_transaction_free(transaction);
2152         return ret;
2153 }
2154
2155 int ref_transaction_commit(struct ref_transaction *transaction,
2156                            struct strbuf *err)
2157 {
2158         struct ref_store *refs = transaction->ref_store;
2159         int ret;
2160
2161         switch (transaction->state) {
2162         case REF_TRANSACTION_OPEN:
2163                 /* Need to prepare first. */
2164                 ret = ref_transaction_prepare(transaction, err);
2165                 if (ret)
2166                         return ret;
2167                 break;
2168         case REF_TRANSACTION_PREPARED:
2169                 /* Fall through to finish. */
2170                 break;
2171         case REF_TRANSACTION_CLOSED:
2172                 BUG("commit called on a closed reference transaction");
2173                 break;
2174         default:
2175                 BUG("unexpected reference transaction state");
2176                 break;
2177         }
2178
2179         ret = refs->be->transaction_finish(refs, transaction, err);
2180         if (!ret)
2181                 run_transaction_hook(transaction, "committed");
2182         return ret;
2183 }
2184
2185 int refs_verify_refname_available(struct ref_store *refs,
2186                                   const char *refname,
2187                                   const struct string_list *extras,
2188                                   const struct string_list *skip,
2189                                   struct strbuf *err)
2190 {
2191         const char *slash;
2192         const char *extra_refname;
2193         struct strbuf dirname = STRBUF_INIT;
2194         struct strbuf referent = STRBUF_INIT;
2195         struct object_id oid;
2196         unsigned int type;
2197         struct ref_iterator *iter;
2198         int ok;
2199         int ret = -1;
2200
2201         /*
2202          * For the sake of comments in this function, suppose that
2203          * refname is "refs/foo/bar".
2204          */
2205
2206         assert(err);
2207
2208         strbuf_grow(&dirname, strlen(refname) + 1);
2209         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2210                 /* Expand dirname to the new prefix, not including the trailing slash: */
2211                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2212
2213                 /*
2214                  * We are still at a leading dir of the refname (e.g.,
2215                  * "refs/foo"; if there is a reference with that name,
2216                  * it is a conflict, *unless* it is in skip.
2217                  */
2218                 if (skip && string_list_has_string(skip, dirname.buf))
2219                         continue;
2220
2221                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2222                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2223                                     dirname.buf, refname);
2224                         goto cleanup;
2225                 }
2226
2227                 if (extras && string_list_has_string(extras, dirname.buf)) {
2228                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2229                                     refname, dirname.buf);
2230                         goto cleanup;
2231                 }
2232         }
2233
2234         /*
2235          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2236          * There is no point in searching for a reference with that
2237          * name, because a refname isn't considered to conflict with
2238          * itself. But we still need to check for references whose
2239          * names are in the "refs/foo/bar/" namespace, because they
2240          * *do* conflict.
2241          */
2242         strbuf_addstr(&dirname, refname + dirname.len);
2243         strbuf_addch(&dirname, '/');
2244
2245         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2246                                        DO_FOR_EACH_INCLUDE_BROKEN);
2247         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2248                 if (skip &&
2249                     string_list_has_string(skip, iter->refname))
2250                         continue;
2251
2252                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2253                             iter->refname, refname);
2254                 ref_iterator_abort(iter);
2255                 goto cleanup;
2256         }
2257
2258         if (ok != ITER_DONE)
2259                 BUG("error while iterating over references");
2260
2261         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2262         if (extra_refname)
2263                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2264                             refname, extra_refname);
2265         else
2266                 ret = 0;
2267
2268 cleanup:
2269         strbuf_release(&referent);
2270         strbuf_release(&dirname);
2271         return ret;
2272 }
2273
2274 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2275 {
2276         struct ref_iterator *iter;
2277         struct do_for_each_ref_help hp = { fn, cb_data };
2278
2279         iter = refs->be->reflog_iterator_begin(refs);
2280
2281         return do_for_each_repo_ref_iterator(the_repository, iter,
2282                                              do_for_each_ref_helper, &hp);
2283 }
2284
2285 int for_each_reflog(each_ref_fn fn, void *cb_data)
2286 {
2287         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2288 }
2289
2290 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2291                                      const char *refname,
2292                                      each_reflog_ent_fn fn,
2293                                      void *cb_data)
2294 {
2295         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2296                                                      fn, cb_data);
2297 }
2298
2299 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2300                                 void *cb_data)
2301 {
2302         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2303                                                 refname, fn, cb_data);
2304 }
2305
2306 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2307                              each_reflog_ent_fn fn, void *cb_data)
2308 {
2309         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2310 }
2311
2312 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2313                         void *cb_data)
2314 {
2315         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2316                                         fn, cb_data);
2317 }
2318
2319 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2320 {
2321         return refs->be->reflog_exists(refs, refname);
2322 }
2323
2324 int reflog_exists(const char *refname)
2325 {
2326         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2327 }
2328
2329 int refs_create_reflog(struct ref_store *refs, const char *refname,
2330                        int force_create, struct strbuf *err)
2331 {
2332         return refs->be->create_reflog(refs, refname, force_create, err);
2333 }
2334
2335 int safe_create_reflog(const char *refname, int force_create,
2336                        struct strbuf *err)
2337 {
2338         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2339                                   force_create, err);
2340 }
2341
2342 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2343 {
2344         return refs->be->delete_reflog(refs, refname);
2345 }
2346
2347 int delete_reflog(const char *refname)
2348 {
2349         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2350 }
2351
2352 int refs_reflog_expire(struct ref_store *refs,
2353                        const char *refname, const struct object_id *oid,
2354                        unsigned int flags,
2355                        reflog_expiry_prepare_fn prepare_fn,
2356                        reflog_expiry_should_prune_fn should_prune_fn,
2357                        reflog_expiry_cleanup_fn cleanup_fn,
2358                        void *policy_cb_data)
2359 {
2360         return refs->be->reflog_expire(refs, refname, oid, flags,
2361                                        prepare_fn, should_prune_fn,
2362                                        cleanup_fn, policy_cb_data);
2363 }
2364
2365 int reflog_expire(const char *refname, const struct object_id *oid,
2366                   unsigned int flags,
2367                   reflog_expiry_prepare_fn prepare_fn,
2368                   reflog_expiry_should_prune_fn should_prune_fn,
2369                   reflog_expiry_cleanup_fn cleanup_fn,
2370                   void *policy_cb_data)
2371 {
2372         return refs_reflog_expire(get_main_ref_store(the_repository),
2373                                   refname, oid, flags,
2374                                   prepare_fn, should_prune_fn,
2375                                   cleanup_fn, policy_cb_data);
2376 }
2377
2378 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2379                                    struct strbuf *err)
2380 {
2381         struct ref_store *refs = transaction->ref_store;
2382
2383         return refs->be->initial_transaction_commit(refs, transaction, err);
2384 }
2385
2386 int refs_delete_refs(struct ref_store *refs, const char *logmsg,
2387                      struct string_list *refnames, unsigned int flags)
2388 {
2389         char *msg;
2390         int retval;
2391
2392         msg = normalize_reflog_message(logmsg);
2393         retval = refs->be->delete_refs(refs, msg, refnames, flags);
2394         free(msg);
2395         return retval;
2396 }
2397
2398 int delete_refs(const char *msg, struct string_list *refnames,
2399                 unsigned int flags)
2400 {
2401         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2402 }
2403
2404 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2405                     const char *newref, const char *logmsg)
2406 {
2407         char *msg;
2408         int retval;
2409
2410         msg = normalize_reflog_message(logmsg);
2411         retval = refs->be->rename_ref(refs, oldref, newref, msg);
2412         free(msg);
2413         return retval;
2414 }
2415
2416 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2417 {
2418         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2419 }
2420
2421 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2422                     const char *newref, const char *logmsg)
2423 {
2424         char *msg;
2425         int retval;
2426
2427         msg = normalize_reflog_message(logmsg);
2428         retval = refs->be->copy_ref(refs, oldref, newref, msg);
2429         free(msg);
2430         return retval;
2431 }
2432
2433 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2434 {
2435         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2436 }